/**
 ******************************************************************************
 * Xenia : Xbox 360 Emulator Research Project                                 *
 ******************************************************************************
 * Copyright 2020 Ben Vanik. All rights reserved.                             *
 * Released under the BSD license - see LICENSE in the root for more details. *
 ******************************************************************************
 */

#include "xenia/vfs/devices/stfs_container_device.h"

#include <algorithm>
#include <queue>
#include <vector>

#include "xenia/base/logging.h"
#include "xenia/base/math.h"
#include "xenia/vfs/devices/stfs_container_entry.h"

#if XE_PLATFORM_WIN32
#include "xenia/base/platform_win.h"
#define timegm _mkgmtime
#endif

namespace xe {
namespace vfs {

uint32_t load_uint24_be(const uint8_t* p) {
  return (static_cast<uint32_t>(p[0]) << 16) |
         (static_cast<uint32_t>(p[1]) << 8) | static_cast<uint32_t>(p[2]);
}
uint32_t load_uint24_le(const uint8_t* p) {
  return (static_cast<uint32_t>(p[2]) << 16) |
         (static_cast<uint32_t>(p[1]) << 8) | static_cast<uint32_t>(p[0]);
}

// Convert FAT timestamp to 100-nanosecond intervals since January 1, 1601 (UTC)
uint64_t decode_fat_timestamp(uint32_t date, uint32_t time) {
  struct tm tm = {0};
  // 80 is the difference between 1980 (FAT) and 1900 (tm);
  tm.tm_year = ((0xFE00 & date) >> 9) + 80;
  tm.tm_mon = (0x01E0 & date) >> 5;
  tm.tm_mday = (0x001F & date) >> 0;
  tm.tm_hour = (0xF800 & time) >> 11;
  tm.tm_min = (0x07E0 & time) >> 5;
  tm.tm_sec = (0x001F & time) << 1;  // the value stored in 2-seconds intervals
  tm.tm_isdst = 0;
  time_t timet = timegm(&tm);
  if (timet == -1) {
    return 0;
  }
  // 11644473600LL is a difference between 1970 and 1601
  return (timet + 11644473600LL) * 10000000;
}

StfsContainerDevice::StfsContainerDevice(const std::string_view mount_path,
                                         const std::filesystem::path& host_path)
    : Device(mount_path),
      name_("STFS"),
      host_path_(host_path),
      mmap_total_size_(),
      base_offset_(),
      magic_offset_(),
      header_(),
      svod_layout_() {}

StfsContainerDevice::~StfsContainerDevice() = default;

bool StfsContainerDevice::Initialize() {
  // Resolve a valid STFS file if a directory is given.
  if (std::filesystem::is_directory(host_path_) &&
      !ResolveFromFolder(host_path_)) {
    XELOGE("Could not resolve an STFS container given path {}",
           xe::path_to_utf8(host_path_));
    return false;
  }

  if (!std::filesystem::exists(host_path_)) {
    XELOGE("Path to STFS container does not exist: {}",
           xe::path_to_utf8(host_path_));
    return false;
  }

  // Map the data file(s)
  auto map_result = MapFiles();
  if (map_result != Error::kSuccess) {
    XELOGE("Failed to map STFS container: {}", map_result);
    return false;
  }

  switch (header_.metadata.volume_type) {
    case XContentVolumeType::kStfs:
      return ReadSTFS() == Error::kSuccess;
      break;
    case XContentVolumeType::kSvod:
      return ReadSVOD() == Error::kSuccess;
    default:
      XELOGE("Unknown STFS Descriptor Type: {}",
             xe::byte_swap(uint32_t(header_.metadata.volume_type.value)));
      return false;
  }
}

StfsContainerDevice::Error StfsContainerDevice::MapFiles() {
  // Map the file containing the STFS Header and read it.
  XELOGI("Mapping STFS Header file: {}", xe::path_to_utf8(host_path_));
  auto header_map = MappedMemory::Open(host_path_, MappedMemory::Mode::kRead);
  if (!header_map) {
    XELOGE("Error mapping STFS Header file.");
    return Error::kErrorReadError;
  }

  auto header_result =
      ReadHeaderAndVerify(header_map->data(), header_map->size());
  if (header_result != Error::kSuccess) {
    XELOGE("Error reading STFS Header: {}", header_result);
    return header_result;
  }

  mmap_total_size_ = header_map->size();

  // If the STFS package is a single file, the header is self contained and
  // we don't need to map any extra files.
  // NOTE: data_file_count is 0 for STFS and 1 for SVOD
  if (header_.metadata.data_file_count <= 1) {
    XELOGI("STFS container is a single file.");
    mmap_.emplace(std::make_pair(0, std::move(header_map)));
    return Error::kSuccess;
  }

  // If the STFS package is multi-file, it is an SVOD system. We need to map
  // the files in the .data folder and can discard the header.
  auto data_fragment_path = host_path_;
  data_fragment_path += ".data";
  if (!std::filesystem::exists(data_fragment_path)) {
    XELOGE("STFS container is multi-file, but path {} does not exist.",
           xe::path_to_utf8(data_fragment_path));
    return Error::kErrorFileMismatch;
  }

  // Ensure data fragment files are sorted
  auto fragment_files = filesystem::ListFiles(data_fragment_path);
  std::sort(fragment_files.begin(), fragment_files.end(),
            [](filesystem::FileInfo& left, filesystem::FileInfo& right) {
              return left.name < right.name;
            });

  if (fragment_files.size() != header_.metadata.data_file_count) {
    XELOGE("SVOD expecting {} data fragments, but {} are present.",
           header_.metadata.data_file_count, fragment_files.size());
    return Error::kErrorFileMismatch;
  }

  for (size_t i = 0; i < fragment_files.size(); i++) {
    auto file = fragment_files.at(i);
    auto path = file.path / file.name;
    auto data = MappedMemory::Open(path, MappedMemory::Mode::kRead);
    if (!data) {
      XELOGI("Failed to map SVOD file {}.", xe::path_to_utf8(path));
      mmap_.clear();
      mmap_total_size_ = 0;
      return Error::kErrorReadError;
    }
    mmap_total_size_ += data->size();
    mmap_.emplace(std::make_pair(i, std::move(data)));
  }
  XELOGI("SVOD successfully mapped {} files.", fragment_files.size());
  return Error::kSuccess;
}

void StfsContainerDevice::Dump(StringBuffer* string_buffer) {
  auto global_lock = global_critical_region_.Acquire();
  root_entry_->Dump(string_buffer, 0);
}

Entry* StfsContainerDevice::ResolvePath(const std::string_view path) {
  // The filesystem will have stripped our prefix off already, so the path will
  // be in the form:
  // some\PATH.foo
  XELOGFS("StfsContainerDevice::ResolvePath({})", path);
  return root_entry_->ResolvePath(path);
}

StfsContainerDevice::Error StfsContainerDevice::ReadHeaderAndVerify(
    const uint8_t* map_ptr, size_t map_size) {
  // Copy header & check signature
  memcpy(&header_, map_ptr, sizeof(StfsHeader));
  if (header_.header.magic != XContentPackageType::kPackageTypeCon &&
      header_.header.magic != XContentPackageType::kPackageTypeLive &&
      header_.header.magic != XContentPackageType::kPackageTypePirs) {
    // Unexpected format.
    return Error::kErrorFileMismatch;
  }

  // Pre-calculate some values used in block number calculations
  blocks_per_hash_table_ =
      header_.metadata.stfs_volume_descriptor.flags.read_only_format ? 1 : 2;

  block_step[0] = kBlocksPerHashLevel[0] + blocks_per_hash_table_;
  block_step[1] = kBlocksPerHashLevel[1] +
                  ((kBlocksPerHashLevel[0] + 1) * blocks_per_hash_table_);

  return Error::kSuccess;
}

StfsContainerDevice::Error StfsContainerDevice::ReadSVOD() {
  // SVOD Systems can have different layouts. The root block is
  // denoted by the magic "MICROSOFT*XBOX*MEDIA" and is always in
  // the first "actual" data fragment of the system.
  auto data = mmap_.at(0)->data();
  const char* MEDIA_MAGIC = "MICROSOFT*XBOX*MEDIA";

  // Check for EDGF layout
  if (header_.metadata.svod_volume_descriptor.features.enhanced_gdf_layout) {
    // The STFS header has specified that this SVOD system uses the EGDF layout.
    // We can expect the magic block to be located immediately after the hash
    // blocks. We also offset block address calculation by 0x1000 by shifting
    // block indices by +0x2.
    if (memcmp(data + 0x2000, MEDIA_MAGIC, 20) == 0) {
      base_offset_ = 0x0000;
      magic_offset_ = 0x2000;
      svod_layout_ = SvodLayoutType::kEnhancedGDF;
      XELOGI("SVOD uses an EGDF layout. Magic block present at 0x2000.");
    } else {
      XELOGE("SVOD uses an EGDF layout, but the magic block was not found.");
      return Error::kErrorFileMismatch;
    }
  } else if (memcmp(data + 0x12000, MEDIA_MAGIC, 20) == 0) {
    // If the SVOD's magic block is at 0x12000, it is likely using an XSF
    // layout. This is usually due to converting the game using a third-party
    // tool, as most of them use a nulled XSF as a template.

    base_offset_ = 0x10000;
    magic_offset_ = 0x12000;

    // Check for XSF Header
    const char* XSF_MAGIC = "XSF";
    if (memcmp(data + 0x2000, XSF_MAGIC, 3) == 0) {
      svod_layout_ = SvodLayoutType::kXSF;
      XELOGI("SVOD uses an XSF layout. Magic block present at 0x12000.");
      XELOGI("Game was likely converted using a third-party tool.");
    } else {
      svod_layout_ = SvodLayoutType::kUnknown;
      XELOGI("SVOD appears to use an XSF layout, but no header is present.");
      XELOGI("SVOD magic block found at 0x12000");
    }
  } else if (memcmp(data + 0xD000, MEDIA_MAGIC, 20) == 0) {
    // If the SVOD's magic block is at 0xD000, it most likely means that it is
    // a single-file system. The STFS Header is 0xB000 bytes , and the remaining
    // 0x2000 is from hash tables. In most cases, these will be STFS, not SVOD.

    base_offset_ = 0xB000;
    magic_offset_ = 0xD000;

    // Check for single file system
    if (header_.metadata.data_file_count == 1) {
      svod_layout_ = SvodLayoutType::kSingleFile;
      XELOGI("SVOD is a single file. Magic block present at 0xD000.");
    } else {
      svod_layout_ = SvodLayoutType::kUnknown;
      XELOGE(
          "SVOD is not a single file, but the magic block was found at "
          "0xD000.");
    }
  } else {
    XELOGE("Could not locate SVOD magic block.");
    return Error::kErrorReadError;
  }

  // Parse the root directory
  uint8_t* magic_block = data + magic_offset_;
  uint32_t root_block = xe::load<uint32_t>(magic_block + 0x14);
  uint32_t root_size = xe::load<uint32_t>(magic_block + 0x18);
  uint32_t root_creation_date = xe::load<uint32_t>(magic_block + 0x1C);
  uint32_t root_creation_time = xe::load<uint32_t>(magic_block + 0x20);
  uint64_t root_creation_timestamp =
      decode_fat_timestamp(root_creation_date, root_creation_time);

  auto root_entry = new StfsContainerEntry(this, nullptr, "", &mmap_);
  root_entry->attributes_ = kFileAttributeDirectory;
  root_entry->access_timestamp_ = root_creation_timestamp;
  root_entry->create_timestamp_ = root_creation_timestamp;
  root_entry->write_timestamp_ = root_creation_timestamp;
  root_entry_ = std::unique_ptr<Entry>(root_entry);

  // Traverse all child entries
  return ReadEntrySVOD(root_block, 0, root_entry);
}

StfsContainerDevice::Error StfsContainerDevice::ReadEntrySVOD(
    uint32_t block, uint32_t ordinal, StfsContainerEntry* parent) {
  // For games with a large amount of files, the ordinal offset can overrun
  // the current block and potentially hit a hash block.
  size_t ordinal_offset = ordinal * 0x4;
  size_t block_offset = ordinal_offset / 0x800;
  size_t true_ordinal_offset = ordinal_offset % 0x800;

  // Calculate the file & address of the block
  size_t entry_address, entry_file;
  BlockToOffsetSVOD(block + block_offset, &entry_address, &entry_file);
  entry_address += true_ordinal_offset;

  // Read block's descriptor
  auto data = mmap_.at(entry_file)->data() + entry_address;

  uint16_t node_l = xe::load<uint16_t>(data + 0x00);
  uint16_t node_r = xe::load<uint16_t>(data + 0x02);
  uint32_t data_block = xe::load<uint32_t>(data + 0x04);
  uint32_t length = xe::load<uint32_t>(data + 0x08);
  uint8_t attributes = xe::load<uint8_t>(data + 0x0C);
  uint8_t name_length = xe::load<uint8_t>(data + 0x0D);
  auto name_buffer = reinterpret_cast<const char*>(data + 0x0E);
  auto name = std::string(name_buffer, name_length);

  // Read the left node
  if (node_l) {
    auto node_result = ReadEntrySVOD(block, node_l, parent);
    if (node_result != Error::kSuccess) {
      return node_result;
    }
  }

  // Read file & address of block's data
  size_t data_address, data_file;
  BlockToOffsetSVOD(data_block, &data_address, &data_file);

  // Create the entry
  // NOTE: SVOD entries don't have timestamps for individual files, which can
  //       cause issues when decrypting games. Using the root entry's timestamp
  //       solves this issues.
  auto entry = StfsContainerEntry::Create(this, parent, name, &mmap_);
  if (attributes & kFileAttributeDirectory) {
    // Entry is a directory
    entry->attributes_ = kFileAttributeDirectory | kFileAttributeReadOnly;
    entry->data_offset_ = 0;
    entry->data_size_ = 0;
    entry->block_ = block;
    entry->access_timestamp_ = root_entry_->create_timestamp();
    entry->create_timestamp_ = root_entry_->create_timestamp();
    entry->write_timestamp_ = root_entry_->create_timestamp();

    if (length) {
      // If length is greater than 0, traverse the directory's children
      auto directory_result = ReadEntrySVOD(data_block, 0, entry.get());
      if (directory_result != Error::kSuccess) {
        return directory_result;
      }
    }
  } else {
    // Entry is a file
    entry->attributes_ = kFileAttributeNormal | kFileAttributeReadOnly;
    entry->size_ = length;
    entry->allocation_size_ = xe::round_up(length, kSectorSize);
    entry->data_offset_ = data_address;
    entry->data_size_ = length;
    entry->block_ = data_block;
    entry->access_timestamp_ = root_entry_->create_timestamp();
    entry->create_timestamp_ = root_entry_->create_timestamp();
    entry->write_timestamp_ = root_entry_->create_timestamp();

    // Fill in all block records, sector by sector.
    if (entry->attributes() & X_FILE_ATTRIBUTE_NORMAL) {
      uint32_t block_index = data_block;
      size_t remaining_size = xe::round_up(length, 0x800);

      size_t last_record = -1;
      size_t last_offset = -1;
      while (remaining_size) {
        const size_t BLOCK_SIZE = 0x800;

        size_t offset, file_index;
        BlockToOffsetSVOD(block_index, &offset, &file_index);

        block_index++;
        remaining_size -= BLOCK_SIZE;

        if (offset - last_offset == 0x800) {
          // Consecutive, so append to last entry.
          entry->block_list_[last_record].length += BLOCK_SIZE;
          last_offset = offset;
          continue;
        }

        entry->block_list_.push_back({file_index, offset, BLOCK_SIZE});
        last_record = entry->block_list_.size() - 1;
        last_offset = offset;
      }
    }
  }

  parent->children_.emplace_back(std::move(entry));

  // Read the right node.
  if (node_r) {
    auto node_result = ReadEntrySVOD(block, node_r, parent);
    if (node_result != Error::kSuccess) {
      return node_result;
    }
  }

  return Error::kSuccess;
}

void StfsContainerDevice::BlockToOffsetSVOD(size_t block, size_t* out_address,
                                            size_t* out_file_index) {
  // SVOD Systems use hash blocks for integrity checks. These hash blocks
  // cause blocks to be discontinuous in memory, and must be accounted for.
  //  - Each data block is 0x800 bytes in length
  //  - Every group of 0x198 data blocks is preceded a Level0 hash table.
  //    Level0 tables contain 0xCC hashes, each representing two data blocks.
  //    The total size of each Level0 hash table is 0x1000 bytes in length.
  //  - Every 0xA1C4 Level0 hash tables is preceded by a Level1 hash table.
  //    Level1 tables contain 0xCB hashes, each representing two Level0 hashes.
  //    The total size of each Level1 hash table is 0x1000 bytes in length.
  //  - Files are split into fragments of 0xA290000 bytes in length,
  //    consisting of 0x14388 data blocks, 0xCB Level0 hash tables, and 0x1
  //    Level1 hash table.

  const size_t BLOCK_SIZE = 0x800;
  const size_t HASH_BLOCK_SIZE = 0x1000;
  const size_t BLOCKS_PER_L0_HASH = 0x198;
  const size_t HASHES_PER_L1_HASH = 0xA1C4;
  const size_t BLOCKS_PER_FILE = 0x14388;
  const size_t MAX_FILE_SIZE = 0xA290000;
  const size_t BLOCK_OFFSET =
      header_.metadata.svod_volume_descriptor.start_data_block();

  // Resolve the true block address and file index
  size_t true_block = block - (BLOCK_OFFSET * 2);
  if (svod_layout_ == SvodLayoutType::kEnhancedGDF) {
    // EGDF has an 0x1000 byte offset, which is two blocks
    true_block += 0x2;
  }

  size_t file_block = true_block % BLOCKS_PER_FILE;
  size_t file_index = true_block / BLOCKS_PER_FILE;
  size_t offset = 0;

  // Calculate offset caused by Level0 Hash Tables
  size_t level0_table_count = (file_block / BLOCKS_PER_L0_HASH) + 1;
  offset += level0_table_count * HASH_BLOCK_SIZE;

  // Calculate offset caused by Level1 Hash Tables
  size_t level1_table_count = (level0_table_count / HASHES_PER_L1_HASH) + 1;
  offset += level1_table_count * HASH_BLOCK_SIZE;

  // For single-file SVOD layouts, include the size of the header in the offset.
  if (svod_layout_ == SvodLayoutType::kSingleFile) {
    offset += base_offset_;
  }

  size_t block_address = (file_block * BLOCK_SIZE) + offset;

  // If the offset causes the block address to overrun the file, round it.
  if (block_address >= MAX_FILE_SIZE) {
    file_index += 1;
    block_address %= MAX_FILE_SIZE;
    block_address += 0x2000;
  }

  *out_address = block_address;
  *out_file_index = file_index;
}

StfsContainerDevice::Error StfsContainerDevice::ReadSTFS() {
  auto data = mmap_.at(0)->data();

  auto root_entry = new StfsContainerEntry(this, nullptr, "", &mmap_);
  root_entry->attributes_ = kFileAttributeDirectory;
  root_entry_ = std::unique_ptr<Entry>(root_entry);

  std::vector<StfsContainerEntry*> all_entries;

  // Load all listings.
  auto& volume_descriptor = header_.metadata.stfs_volume_descriptor;
  uint32_t table_block_index = volume_descriptor.file_table_block_number();
  for (size_t n = 0; n < volume_descriptor.file_table_block_count; n++) {
    const uint8_t* p = data + BlockToOffsetSTFS(table_block_index);
    for (size_t m = 0; m < kSectorSize / 0x40; m++) {
      const uint8_t* name_buffer = p;  // 0x28b
      if (name_buffer[0] == 0) {
        // Done.
        break;
      }
      uint8_t name_length_flags = xe::load_and_swap<uint8_t>(p + 0x28);
      uint32_t allocated_block_count = load_uint24_le(p + 0x2C);
      uint32_t start_block_index = load_uint24_le(p + 0x2F);
      uint16_t path_indicator = xe::load_and_swap<uint16_t>(p + 0x32);
      uint32_t file_size = xe::load_and_swap<uint32_t>(p + 0x34);

      // both date and time parts of the timestamp are big endian
      uint16_t update_date = xe::load_and_swap<uint16_t>(p + 0x38);
      uint16_t update_time = xe::load_and_swap<uint16_t>(p + 0x3A);
      uint32_t access_date = xe::load_and_swap<uint16_t>(p + 0x3C);
      uint32_t access_time = xe::load_and_swap<uint16_t>(p + 0x3E);
      p += 0x40;

      StfsContainerEntry* parent_entry = nullptr;
      if (path_indicator == 0xFFFF) {
        parent_entry = root_entry;
      } else {
        parent_entry = all_entries[path_indicator];
      }

      std::string name(reinterpret_cast<const char*>(name_buffer),
                       name_length_flags & 0x3F);
      auto entry = StfsContainerEntry::Create(this, parent_entry, name, &mmap_);

      // bit 0x40 = consecutive blocks (not fragmented?)
      if (name_length_flags & 0x80) {
        entry->attributes_ = kFileAttributeDirectory;
      } else {
        entry->attributes_ = kFileAttributeNormal | kFileAttributeReadOnly;
        entry->data_offset_ = BlockToOffsetSTFS(start_block_index);
        entry->data_size_ = file_size;
      }
      entry->size_ = file_size;
      entry->allocation_size_ = xe::round_up(file_size, kSectorSize);

      entry->create_timestamp_ = decode_fat_timestamp(update_date, update_time);
      entry->access_timestamp_ = decode_fat_timestamp(access_date, access_time);
      entry->write_timestamp_ = entry->create_timestamp_;

      all_entries.push_back(entry.get());

      // Fill in all block records.
      // It's easier to do this now and just look them up later, at the cost
      // of some memory. Nasty chain walk.
      // TODO(benvanik): optimize if flag 0x40 (consecutive) is set.
      if (entry->attributes() & X_FILE_ATTRIBUTE_NORMAL) {
        uint32_t block_index = start_block_index;
        size_t remaining_size = file_size;
        while (remaining_size && block_index != 0xFFFFFF) {
          size_t block_size =
              std::min(static_cast<size_t>(kSectorSize), remaining_size);
          size_t offset = BlockToOffsetSTFS(block_index);
          entry->block_list_.push_back({0, offset, block_size});
          remaining_size -= block_size;
          auto block_hash = GetBlockHash(data, block_index);
          block_index = block_hash->level0_next_block();
        }

        // Check that the number of blocks retrieved from hash entries matches
        // the block count read from the file entry
        if (entry->block_list_.size() != allocated_block_count) {
          XELOGW(
              "STFS failed to read correct block-chain for entry {}, read {} "
              "blocks, expected {}",
              entry->name_, entry->block_list_.size(), allocated_block_count);
          assert_always();
        }
      }

      parent_entry->children_.emplace_back(std::move(entry));
    }

    auto block_hash = GetBlockHash(data, table_block_index);
    table_block_index = block_hash->level0_next_block();
    if (table_block_index == 0xFFFFFF) {
      break;
    }
  }

  return Error::kSuccess;
}

size_t StfsContainerDevice::BlockToOffsetSTFS(uint64_t block_index) const {
  // For every level there is a hash table
  // Level 0: hash table of next 170 blocks
  // Level 1: hash table of next 170 hash tables
  // Level 2: hash table of next 170 level 1 hash tables
  // And so on...
  uint64_t base = kBlocksPerHashLevel[0];
  uint64_t block = block_index;
  for (uint32_t i = 0; i < 3; i++) {
    block += ((block_index + base) / base) * blocks_per_hash_table_;
    if (block_index < base) {
      break;
    }

    base *= kBlocksPerHashLevel[0];
  }

  return xe::round_up(header_.header.header_size, kSectorSize) + (block << 12);
}

uint32_t StfsContainerDevice::BlockToHashBlockNumberSTFS(
    uint32_t block_index, uint32_t hash_level) const {
  uint32_t block = 0;
  if (hash_level == 0) {
    if (block_index < kBlocksPerHashLevel[0]) {
      return 0;
    }

    block = (block_index / kBlocksPerHashLevel[0]) * block_step[0];
    block +=
        ((block_index / kBlocksPerHashLevel[1]) + 1) * blocks_per_hash_table_;

    if (block_index < kBlocksPerHashLevel[1]) {
      return block;
    }

    return block + blocks_per_hash_table_;
  }

  if (hash_level == 1) {
    if (block_index < kBlocksPerHashLevel[1]) {
      return block_step[0];
    }

    block = (block_index / kBlocksPerHashLevel[1]) * block_step[1];
    return block + blocks_per_hash_table_;
  }

  // Level 2 is always at blockStep1
  return block_step[1];
}

size_t StfsContainerDevice::BlockToHashBlockOffsetSTFS(
    uint32_t block_index, uint32_t hash_level) const {
  uint64_t block = BlockToHashBlockNumberSTFS(block_index, hash_level);
  return xe::round_up(header_.header.header_size, kSectorSize) + (block << 12);
}

const StfsHashEntry* StfsContainerDevice::GetBlockHash(const uint8_t* map_ptr,
                                                       uint32_t block_index) {
  // Offset for selecting the secondary hash block, in packages that have them
  uint32_t secondary_table_offset =
      header_.metadata.stfs_volume_descriptor.flags.root_active_index
          ? kSectorSize
          : 0;

  // If this is read_only_format then it doesn't contain secondary blocks, no
  // need to check upper hash levels
  if (header_.metadata.stfs_volume_descriptor.flags.read_only_format) {
    secondary_table_offset = 0;
  } else {
    // Not a read-only package, need to check each levels active index flag to
    // see if we need to use secondary block or not

    // Check L2 active index flag...
    if (header_.metadata.stfs_volume_descriptor.allocated_block_count >
        kBlocksPerHashLevel[1]) {
      auto hash_offset = BlockToHashBlockOffsetSTFS(block_index, 2);
      auto hash_table = map_ptr + hash_offset + secondary_table_offset;

      auto record =
          (block_index / kBlocksPerHashLevel[1]) % kBlocksPerHashLevel[0];
      auto record_data =
          reinterpret_cast<const StfsHashEntry*>(hash_table + record * 0x18);
      secondary_table_offset =
          record_data->levelN_activeindex() ? kSectorSize : 0;
    }

    // Check L1 active index flag...
    if (header_.metadata.stfs_volume_descriptor.allocated_block_count >
        kBlocksPerHashLevel[0]) {
      auto hash_offset = BlockToHashBlockOffsetSTFS(block_index, 1);
      auto hash_table = map_ptr + hash_offset + secondary_table_offset;

      auto record =
          (block_index / kBlocksPerHashLevel[0]) % kBlocksPerHashLevel[0];
      auto record_data =
          reinterpret_cast<const StfsHashEntry*>(hash_table + record * 0x18);
      secondary_table_offset =
          record_data->levelN_activeindex() ? kSectorSize : 0;
    }
  }

  auto hash_offset = BlockToHashBlockOffsetSTFS(block_index, 0);
  auto hash_table = map_ptr + hash_offset + secondary_table_offset;

  auto record = block_index % kBlocksPerHashLevel[0];
  auto record_data =
      reinterpret_cast<const StfsHashEntry*>(hash_table + record * 0x18);

  return record_data;
}

uint32_t StfsContainerDevice::ReadMagic(const std::filesystem::path& path) {
  auto map = MappedMemory::Open(path, MappedMemory::Mode::kRead, 0, 4);
  return xe::load_and_swap<uint32_t>(map->data());
}

bool StfsContainerDevice::ResolveFromFolder(const std::filesystem::path& path) {
  // Scan through folders until a file with magic is found
  std::queue<filesystem::FileInfo> queue;

  filesystem::FileInfo folder;
  filesystem::GetInfo(host_path_, &folder);
  queue.push(folder);

  while (!queue.empty()) {
    auto current_file = queue.front();
    queue.pop();

    if (current_file.type == filesystem::FileInfo::Type::kDirectory) {
      auto path = current_file.path / current_file.name;
      auto child_files = filesystem::ListFiles(path);
      for (auto file : child_files) {
        queue.push(file);
      }
    } else {
      // Try to read the file's magic
      auto path = current_file.path / current_file.name;
      auto magic = ReadMagic(path);

      if (magic == XContentPackageType::kPackageTypeCon ||
          magic == XContentPackageType::kPackageTypeLive ||
          magic == XContentPackageType::kPackageTypePirs) {
        host_path_ = current_file.path / current_file.name;
        XELOGI("STFS Package found: {}", xe::path_to_utf8(host_path_));
        return true;
      }
    }
  }

  if (host_path_ == path) {
    // Could not find a suitable container file
    return false;
  }
  return true;
}

}  // namespace vfs
}  // namespace xe